He opened his mouth to summon help, but no sound came.

There was still time, perhaps, for him to summon help from the base.

Something was coming their way, and it wasn't as if they could summon help.

But after quickly making sure that the driver had found a way to summon help, he was gone.

No, they probably knew - that two men had gotten away to summon help.

He had summoned medical help from the Enterprise to identify the most serious cases and get them out first.

She was right, but he* had no idea how to summon help when he did not even know where they were.

By the time she summoned help from there, it would be too late.

He summoned help, and I've been holding them off for the last minute.

She apparently was able to keep me from summoning help to deal with her.