This spell causes confusion in the targets, making them unable to determine their actions. Roll on the following table at the start of each subject’s turn each round to see what it does in that round. (...) Any confused character who is attacked automatically attacks its attackers on its next turn, as long as it is still confused when its turn comes.

Hey, I just realized that you couldn't cast Sabotage Construct. You moved into the web, then got grappled by the web, which means you can't cast spells with somatic components.

Grappled: A grappled creature is restrained by a creature,
trap, or effect. Grappled creatures cannot move and take a –4
penalty to Dexterity. A grappled creature takes a –2 penalty
on all attack rolls and combat maneuver checks, except those
made to grapple or escape a grapple. In addition, grappled
creatures
can take no action that requires two hands to
perform. A grappled character who attempts to cast a spell or
use a spell-like ability must make a concentration check (DC
10 + grappler’s CMB + spell level, see page 206), or lose the
spell. Grappled creatures cannot make attacks of opportunity.
A grappled creature cannot use Stealth to hide from
the creature grappling it, even if a special ability, such as
hide in plain sight, would normally allow it to do so. If
a grappled creature becomes invisible, through a spell or
other ability, it gains a +2 circumstance bonus on its CMD
to avoid being grappled, but receives no other benefit.

Grappled or Pinned: Casting a spell while you have the
grappled or pinned condition is difficult and requires a
concentration check (DC 10 + the grappler’s CMB + the
level of the spell you’re casting). Pinned creatures can
only cast spells that do not have somatic components.

Several special immunities are granted while you have 50% or more of your current max HP:
Ability/level damage/drain can't drop a score/level below half its original amount. (not including bonuses from items or spells, etc.)