Since he was being polite this visit, Loki merely stood patiently with his basket of muffins and waited for the resident heroes to assemble in response to the blaring alarms. The Watchtower residents were caught rather flat-footed, not expecting a "villain" to appear suddenly in their own headquarters. This would be a good learning experience for them Loki congratulated himself piously.
The heroes arrived ready for battle but uncertain how to treat the visitor standing calmly in the middle of the room carrying an unthreatening (but rather tempting) basket of muffins. Loki calmly surveyed the heros and weapons ranged against him, rather enjoying the chaos (and the attention). He didn't think they would attack unless provoked, but he had enshrouded himself in an invisible magical shield just in case.
The standoff between the confused heroes and the amused villain was broken when Superman arrived, breathless from his quick return to the Watchtower after hearing the alert while out in space repositioning one of their satellites. He had zoomed back to help defend his friends, only to find it unnecessary. "Mother! What are you doing here?"
Loki couldn't restrain his smile in response to his son's words. He had shed happy tears the first time his youngest had tentatively called him "mother" and the joy at the endearment had not yet worn off. While some of the heros seemed surprised, the majority (the ones most thought of as the core group) were not. It seemed his son was not only willing to acknowledge their relationship publicly, but had already shared the news with some of his closest companions. Loki's heart swelled with love. It was definitely worth any minor irritations caused by dealing with these "superheros" to have a closer relationship with his long-lost son. As Kal-El swept him into a crushing hug Loki resolved to be on his best behavior so as to not embarrass his son amongst his little friends.
Of course, best behavior is a relative thing, and his restraint didn't last long once the de facto leader of the group stalked forward, black cape swirling, to interrupt the moment and confront the pair...