Why was gerund not using in this sentence as parallel balance?

In the following sentence, why the author uses ‘stole’ and ‘stood’ instead of ‘stealing’ and ‘standing’, since the author use ‘seeing’ the gerund at the second clause.

An elderly seaman came to the gate and paused irresolute, then seeing all was quiet, stole cautiously on to the jetty, and stood for some time gazing curiously down on the deck of the billyboy Mary Ann lying alongside.