Tony swore to himself as he tried to staunch the blood flow. He had been undercover only to be ambushed by one of the good guys. No backup, no nothing, no one watching his six. He couldn't believe it; he had lasted at NCIS 6 years only to end up here in some back alley behind a brothel. "Damn it! that'll teach me to listen to some feebie's cockamamie plan" he gasps to himself. He moans through the pain, he's coughing up blood now; it's slowly filling his lungs barely enough oxygen left to breathe in and out.
It hurts, he thinks to himself. He had never thought about it before, with the plague they had him so drugged up he couldn't feel his lungs dying but god now shot to death, betrayed by his source, it hurt so damn bad. "How could I have been stupid? …oh god." What is Gibbs gonna say, he'll never forgive me for this, they'll be standing over my body in autopsy and I bet not even Ducky will be able to tell a story or so I'd hope.
Tony feels the tears falling from his eyes, tracking down his cooling skin, he really couldn't believe it, his end was close, but still he had a minute or two and god he hoped it was enough as he started to crawl over to a bare wall. Lord knows McGee will be the one to find this, he just knew it but he had to tell them. They needed the truth; they needed to know he loved them all, even freaking Ziva David was important to him. And of course, his phone and badge were at home. But he had already solved that one, he had written in his own blood on his ripped tee tossed aside in his haste to hold his side together "Call Gibbs-NCIS." Not the best way to get a message to the man but it couldn't be helped, now to write a bigger one on this ugly alley wall he was propped up on. He had to conserve energy so he tries to breathe through the pain as he begins to fade in an out.
But, at the very last moment he can, he reaches the wall and with one hand gathers his blood up enough to leave a final note. On one side, he writes "Et Tu Brutus," such a poetic irony that this fallen soldier never saw coming. It was a message only his team would understand when they investigate. And the lord only knew they would tear apart the FBI to get the bastard. And with a final breathe he gets a sloppy "I'm sorry" written as his eyes fall shut and he slumps down the wall.
Agent Dinozzo's life ended on a dark night, betrayed by those he trusted, and leaving only a dozen of people behind that he truly loved. He wasn't around to see the aftermath or to see how many lives would truly be affected by the loss of his life.