trialRoute runtime even if routing only two nets

hi,

We have a very weired shape block with below design info

** info: there are 24727 modules.
** info: there are 624875 stdCell insts.
** info: there are 52 Pad insts.
** info: there are 1026 macros.
** info: there are 7190 multi-height stdCell insts (2 stdCells)

the congestion number from the previous step run
Overflow: 259143 = 144067 (0.70% H) + 115077 (0.48% V) 

because trialRoute takes time and I wanted to try out insertBuffer only on two nets, I set all other nets as skipRouting but those two but still trialRoute is running since 17hrs. Below is what I'm doing and the log output from trailRoute. The encounter version is v10.12-s181_1 (64bit) 

velocity 26> set allNets [dbGet top.nets] 
velocity 26> dbSet $allNets.skipRouting true
velocity 27> dbset [dbGet -p top.nets.name TP_JtScanClk2].skipRouting false
velocity 28>  dbset [dbGet -p top.nets.name BP_TCK].skipRouting false
velocity 29> insertRepeater -rule data/repeaterStitch.rule -selNet data/stich_nets.names -outfile data/repeaterInsertion.violations -keepPort 

#################################################################################
# Design Stage: PreRoute
# Design Mode: 90nm
# Analysis Mode: non-MMMC non-OCV
# Extraction Mode: default
# Delay Calculation Options: engine=default signOff=true SIAware=false(opt)
# Switching Delay Calculation Engine to feDC
#################################################################################
*** Starting trialRoute (mem=3386.1M) ***

**WARN: (ENCDB-2078):   Output pin VDD18_TMON_S of instance PA/TMONW0_S is connected to power net PA_VDD18_TMON0_S.  This can create a short circuit if the output is 0.  Check the connectivity in the netlist.

**WARN: (ENCDB-2078):   Output pin VDD18_TMON_S of instance PA/TMONW0_P is connected to power net PA_VDD18_TMON0_S.  This can create a short circuit if the output is 0.  Check the connectivity in the netlist.

There are 0 pin guide points passed to trialRoute.

Options:  -noPinGuide

Nr of prerouted/Fixed nets = 648912
routingBox: (-20202000 -20652000) (20201840 20651200)
coreBox:    (-20200000 -20650000) (20199840 20649200)

 Thanks,

Nishant