How could EMP look like that?

The complaint is as follows: If the EMP created a visible effect like the one we see in the film, all of the crew would be dead. So to explain: this is a VFX gaffe or something that falls under the Black Box (EMP has evolved to look like that) so it shouldn't even be discussed (this is the Apologetics section, though, so we'll continue), but other than those two reasonable explanations, we could also say that they were not strictly speaking in technical terms. Such is language. Just as Kleenex, a specific brand, has come to mean every type of facial tissue EMP- to them- is a general concept of an Electro Magnetic Pulse which disables electrical systems... even if it is not generated like our EMP or anything like it for that matter. Consider their Hovercrafts. This happens a lot with technological terms... consider internet terms which used now aren't always what they used to mean- BBS, ICQ, DVD, etc.

Why is the lobby pristine?

When the bomb blows up, bodies are missing and many think the pillars have healed (there is some visible damage towards the end of the shot though). Chalk it up to Elasticity.