The Silkmen dominated the match, but somehow their defensive inadequacies managed to hand Torquay an undeserved draw.
Macclesfield were out of the traps quickly and should have scored in the fourth minute when Matthew Tipton headed onto the crossbar from close range.
Gulls goalkeeper Nathan Abbey then made two acrobatic saves to keep out Swailes headers, before the visitors took the lead against the run of play after 33 minutes when Kevin McIntyre's slip allowed Lee Mansell to fire home a low 20-yard drive.
Macc should have levelled almost immediately but John Miles nodded a simple header wide.
The hosts eventually got their equaliser two minutes before the break when Abbey could not hold McIntyre's fierce free-kick, gifting skipper David Morley a simple chance from the six-yard line.
Town came out strongly at the start of the second half and went in front when Martin Bullock dipped his shoulder before curling a 20-yard drive to the top corner.
Torquay finally came out of their shells and equalised in the 67th minute when Lee Andrews crossed for the unmarked Lee Thorpe to head home at the far post.
Both sides then had chances to take the game by the scruff of the neck with Bullock carving out an opening for Miles, who slotted wide from 15 yards, before United sub Chris McPhee forced a brilliant save from home goalkeeper Tommy Lee.
However, Lee could do little when Thorpe then sprang the offside trap before delivering a pinpoint cross which Jamie Ward met with a stunning half-volley into the roof of the net.
Macclesfield looked to be dead and buried, but deep in injury-time a McIntyre drive came back off the line for Swailes to hook home the equaliser from close range.