How long do you have to stay hidden after getting spotted? Feels like 5 minutes
After a few seconds, the enemy will assume you are where you were last spotted. They will proceed to shoot in the general area and maybe investigate. Then, a minute later, they will call in that they've lost sight of you and definitely investigate the area you were last spotted. After searching for about a minute, they will call in that they can't find you or, if you've left some corpses or sleepers, they'll go into light alert mode, changing up their movement, as well as being more observant. This won't end for a LONG time.
Best thing to do is use their movements as a guide. Lose sight of them, then move around them. They are mega jumpy at that stage, and distracting them will be easy, but they are also more trigger happy when they have an idea where you are.
This isn't MGS2 or 3, guards aren't retarded goldfish. They won't assume the crazy horned super soldier just up and left after killing one or two of their dudes.
Roll with the punches, and change with their changes.