Running down the corridor Mickey and Peter peeled off from the others and towards the computer classrooms to get the students out whilst further on down the corridor K9 caught up to the Doctor, Rose, Sarah Jane and Kenny as it appeared from around the corner.
"Master" It said.
"Come on boy! Good boy" The Doctor encouraged with a quick pat on it's head as they carried on running.
Reaching a classroom Mickey and Peter burst in to find the students typing furiously and completely focused on their computers.
"Ok listen everyone we've got to get out of here!" Mickey shouted. They all ignored him, even when he tried waving his hand in front of one of their faces. "What do we do?" He asked, turning to Peter, who looked just as stumped.
Meanwhile the Doctor, Rose, Sarah Jane, Kenny and K9 had reached the kitchens. Immediately the Doctor began to try and unlock the barrels with the Sonic.
"They've been deadlocked sealed! Finch must have done it! I can't open them!" He said in frustration.
"The vats would not withstand a direct hit from my laser but my batteries are failing" K9 spoke up.
"Right everyone out of the back door K9 stay with me" The Doctor instructed. Everyone nodded and left through the loading bay door.
In the classroom Peter and Mickey were still looking for a way to get the students away from the computers. Mickey was trying to use the computer on the teacher's desk, which was showing the same program. Peter, however, had become interested in in the large bunch of wires that ran from the computers to the wall where they were covered up by a plastic casing. The casing ran along the top of the wall and then back down again, to a single plug. Peter walked over and crouched down besides it. Checking the wires and students one last time he pulled it out. Sparks burst out from the plug as the computers all shut down. The students had also all become unplugged from the computers, looking around in puzzlement.
"Everyone get out! Now!" Peter told them
"Come one! Move! Let's go! Let's go!" Mickey encouraged as he and Peter led the confused students out.
The Krilitiains were travelling through the school as the hunted the Doctor, reaching the main staircase they all put on their human illusions again.
In the kitchens the Doctor was gathering together all the barrels of oil he could find as K9 watched.
"Capacity for only one shot master, for maximum impact I must be stationed directly besides the vat" It told him, who stopped what he was doing and looked at the dog with horrible realisation.
"But you'll be trapped inside?" He told K9 as he came over and crouched in front of it.
"That is correct" K9 responded.
"I can't let you do that" The Doctor said.
"No alternative possible master" K9 replied. A Krilitiain's screech distracted the Doctor's gaze for a moment before he turned back to K9.
"Goodbye old friend" He said quietly.
"Goodbye master" K9 replied. The Doctor placed a hand on the side of K9's head.
"You good dog" He told it.
"Affirmative" K9 responded, twitching it's two small satellite dish ears. The Doctor drew his hand away and looked at the dog once last time before he ran off to the back door. K9 wheeled itself nearer to the barrels. The Doctor burst out of the back doors, where Sarah Jane was waiting anxiously.
"Where's K9?" She asked as the Doctor locked the doors.
"We need to run" The Doctor told her as he began to run away from the doors.
"Where is he? What have you done!?" Sarah Jane shouted angrily as he came back and dragged her away.
Brother Lassar and the other Krilitiains had reached the kitchens.
"When we find him eat him if you must but bring me his brains" Brother Lassar ordered. Outside the Doctor and Sarah Jane were running hand in hand as far away as they could get from the kitchens. K9 lifted it's head up a little as the Krilitiains found it. "The little dog with the nasty bite? Not so powerful now are you?" Brother Lassar taunted. In response K9 fired a single laser shot at the barrels of oil. The barrels exploded, sending oil all over all of the Krilitiains. At the front doors all of the students were running out of the school.
"Come on guys! Lets go! Lets go!" Mickey shouted as he and Peter hurried them out and away from the school. Inside the kitchens all of the Krilitiains were coated in the oil. Some were crying out in pain, covering the parts of their skin which hat been hit. Brother Lassar stood alone in not showing pain as he scowled at K9.
"You bad dog" He hissed.
"Affirmative" K9 responded. The kitchen exploded. The blast destroyed half of the school, shattering windows and obliterating any evidence of the Krilitiain's work. Among the falling papers, blown from the ruined building, the students were cheering and hugging each other. Among them Rose, Peter, Mickey and Kenny were all also cheering in relief.
"Yes!" Kenny cheered. Melissa, now free of the Krilitiain's oil, looked at him.
"Did you have something to do with this?" She asked with a grin.
"Yeah I did" Kenny replied confidently. Melissa's looked stunned.
"Oh my god! Kenny blew up the school! It was Kenny!" She announced to the students as she took
Kenny, who was now blushing madly, by the hand and lead him into the middle of the crowd. The students cheered and began chanting his name as Kenny was treated like a hero. The only two people not joining the celebrations was the Doctor and Sarah Jane, who'd learnt of K9's fate.
"I'm sorry" The Doctor said quietly.
"It's all right, he was just a, daft metal dog" She said, though not meeting his gaze. "Fine, really" She tried to insist, but her voice was wobbling as the Doctor pulled her into a one armed embrace as she wiped away a tear.
A few hours later in a quiet London park Sarah Jane found what she was looking for. the Tardis was parked on a gravel path that ran in between small decorative hedges. As she reached the door the Doctor stepped out and spotted her.
"Cup of tea?" He asked with a smile before letting her walk in as he followed her and shut the door behind them. As Sarah Jane entered she looked around the console room where Rose, Peter and Mickey were stood.
"You've redecorated" Sarah Jane said turning back to the Doctor.
"Do you like it?" He asked, still smiling.
"Oh I do yeah, I preferred it as it was but it'll do" She replied, looking round the centre console.
"I love it" Rose said with a smile.
"Hey you what's forty seven times three hundred and sixty nine?" Sarah Jane asked with a smile. Rose shrugged.
"No idea it's gone now the oils faded" She replied.
"But your still clever, more than a match for him" Sarah Jane told her as she came over to her with a quick glance at the Doctor.
"You and me both" Rose replied before she turned her to the Doctor, who was fiddling with the console. "Doctor?" She asked, reminding him of something.
"Um, we're about to head off but you could come with us?" He asked Sarah Jane hopefully. A moment passed as Sarah Jane looked from him to an encouraging Rose with Peter and Mickey stood just behind her.
"No" She said with a sigh. "I can't do this any more, besides I've got a much bigger adventure ahead" She told them all. "Time I stopped waiting for you and found a life of my own" She told the Doctor, who's smile faded a little.
"Can I come?" Mickey suddenly asked. Everyone turned to him in surprise. "Not with you," He quickly said to Sarah Jane. "I mean with you?" He asked the Doctor. "Cause I'm not the tin dog and I wanna see what's out there" He added.
"Oh go on Doctor, Sarah Jane Smith and Mickey Smith you need a Smith on board" Sarah Jane encouraged when the Doctor hesitated.
"Okay then, as long as you two can at least try and get on?" He said to both Mickey and Peter. Peter shrugged.
"Sure no problem I could do with a laugh" He said said by way of agreeing.
"Rose is that ok?" Mickey then asked her as she hadn't said anything.
"No, great, why not?" She said, not turning to face him, Sarah Jane, however, saw her expression.
"Well, I better go" Sarah Jane said after and awkward silence. She pulled Rose to the side a little, knowing she wanted to talk.
"What do I do? Do I stay with him?" Rose asked her quietly as she glanced at the Doctor, who was talking to Peter and Mickey.
"Yes, some things are worth getting your heart broken for" Sarah Jane told her before she hugged her goodbye. "Find me if you need to one day, find me" She said as they parted before she walked off to the door where the Doctor had walked over to the walk her out. Leaving the Tardis together they stood looking out at the park for a moment. "It's daft but I haven't ever thanked you for that time and like I said I wouldn't have missed it for the world" She told him.
"Something to tell the grand kids" The Doctor replied with a smile.
"Oh, I think it'll be someone else's grand kids now" She said. The Doctor seemed to realise what she meant.
"Right yes, sorry I didn't get a chance to ask, you haven't, there hasn't been anyone you know?" He tried to ask.
"Well, there was this one guy I travelled with him for a while, but he was tough act to follow" Sarah Jane replied. They both smiled, knowing who she meant. "Goodbye Doctor" She said her voice wobbling again.
"Oh it's not goodbye" The Doctor told her.
"Say it please, this time, say it" She insisted.
"Goodbye" He said before smiling broadly. "My Sarah Jane" He added as he gave her a firm hug, lifting her off the ground a little. There then a moment where they both stood smiled at each other before the Doctor walked back into the Tardis. Sarah Jane turned her back on the ship and started walking away as the Tardis began setting off. Turning to see the last of it disappear she felt tears in her eyes as she watched it go. It was only when the Tardis had vanished did she see the Doctor's final surprise.
"K9!" She cried out as a brand new K9 wheeled itself towards her from where the Tardis had been stood.
"Mistress" It said in the same, but slightly clearer voice as before.
"But you were blown up?" She asked, crouching in front of it.
"Master rebuilt me my systems are much improved with new omni-fleible hyperlink facilites" K9 told her. Sarah Jane gave a little sigh.
"He replaced you with a brand new model" She said.
"Affirmative" K9 said.
"Yeah, he does that come on you home, we've got work to do" She said, standing up and beginning to walk out of the park.
"Affirmative" K9 replied as it wheeled alongside Sarah Jane as they travelled down the path together.
