Hulk gets transported via the Bifrost and ends up right next to Dr.Strange. But how did he know who Dr.Strange was to blurt out about Thanos? As far as I know these two haven't met anywhere before.
Of all the Marvel movies, Dr.Strange is the only one that I haven't seen, so I'm guessing Hulk had an appearance there, though it looks very unlikely?
If not, I wonder how Banner knew the persons standing right before him are special and not ordinary citizens.