Factual error: Take a look at Google Earth - the section of the Golden Gate Bridge Magneto breaks off (about a mile - tower to tower plus a section each end) isn't anywhere near long enough to reach Alcatraz from anywhere on the mainland.
Factual error: After the troops are mobilized to fight against the Brotherhood and guard the cure clinics, they make a big show of them turning in their M16s and other metallic items and getting their plastic weapons so Magneto can't use the metal against them. But they wouldn't have had their M16s, to begin with; you pick up your weapon after you arrive for mobilization at your unit. They would have shown up unarmed and then had the plastic weapons issued to them right after they reported for duty. (Most likely, the scene was made just to get the point across to the audience that they need to get rid of all metal and to look flashy). Prior to the President responding to Magneto's declaration of war by mobilizing the troops, the cure clinics were guarded by civilian law enforcement, not US troops.
Factual error: When Magneto has moved the Golden Gate Bridge, we see the President looking at a Satellite Image of Magneto's work. In this image, Alcatraz Island is bigger and closer to the shore than it is in real life.
Chosen answer: 1) Apparently the combination of Logan's unbreakable skeleton and healing factor was enough to keep Jean from shredding him - it's possible to see his body getting damaged and repairing itself in a few shots. 2) Because, while he's capable of getting close to her mostly intact, the same isn't really true of anything he might be wearing or holding, so any cure syringe he carried with him would be destroyed. 3) Who knows? Given her extreme power level, the cure might or might not have worked, and, considering the final shot of the movie, which suggests that the cure isn't permanent anyway, her powers would likely return before long.
Tailkinker ★