That’s Idris Elba saying goodbye to Heimdall, his character from the Thor movies (and one of Thanos’ first victims in Infinity War), which seems to imply that he won’t be coming back for Avengers 4. However, other than some reshoots that are happening in the fall, most of the filming for Avengers 4 has already been done. That means Elba could just as easily be indicating that Avengers 4 is the end of his time as the all-seeing guardian of the Bifröst—but it seems like it’s the end either way.

On another note, if Elba really is done, Heimdall’s death being permanent would probably be the least surprising of the pre-Gauntlet Infinity War deaths. His character has had fewer and fewer things to do with every appearance he makes, and now that Thor’s new axe weapon can open the Bifröst, Heimdall is even more superfluous. If Tom Hiddleston tweets a goodbye to Loki, then we can start believing that some of these deaths are going to stick.